1. Field of the Invention:
The present invention relates to a brush of a scrubber and, in particular, to a brush for brushing wafers without scraping them.
2. Description of Prior Art:
Referring to FIG. 1, a scrubber produced by the DNS company and widely used in six-inch-wafer Facilities to brush wafers is shown. The scrubber includes) a rotatable disc 10 for holding a wafer by vacuum; a brush arm 12 having one end supported by a rotatable shaft 122 and the other end provided with a brush 2 to brush the wafer held by the disc 10; a brush-rest 14 on which the brush 2 rests when not in use; a deionized water (DIW) rinse nozzle for spouting deionized water to lubricate the wafer so that the brush 2 moves smoothly over it; a N.sub.2 -blow nozzle 164 for blowing nitrogen to dry the wafer; and a jet nozzle 18 connected to a rotatable shaft 184 via a jet nozzle arm 182 for spouting water to rinse the wafer.
As shown in FIG. 2 and 3, the brush 2 of the scrubber comprises a sleeve 22, a cap member 24 and a brushing member 26.
The sleeve 22 has a first end 222a and a second end 222b. At the first end 222a, the sleeve 22 is provided with an inner flange 224 for holding the brushing member 26 within the sleeve, and an outer flange 226 which mates with the brush-rest 14 shown in FIG. 1, an arrangement which allows the whole brush 2 to rest on the brush-rest 14 when not in use. At the second end 222b, the inner wall 222 of the sleeve 22 is provided with recesses 228.
On its outer periphery, the cap member 24 has a continuous thread 244 and engaging portions 242. By means of the continuous thread 244, the cap member 24 can be screwed together with the brush arm 12 shown in FIG. 1. By means of the engaging portions 242, the cap member 24 can be attached to the recesses 228 of the sleeve 22.
The brushing member 26, which is received in the sleeve 22, is made of a material, such as polyvinyl acetate (PVA). Also, the brushing member 26 has a first portion 262 and a second portion 264. The diameter of the first portion 262 is greater than that of the second portion 264 so that the first portion 262 is held by the inner flange 224 of the sleeve 22, and the second portion 264 protrudes from the sleeve 22 to brush the wafer.
However, the brush 2 of the prior art has disadvantages. Referring to FIG. 4, if the height of the brush 2 is not properly set with respect to the safer or the surface of the wafer is too uneven, pressure applied to the brushing member 26 will be excessive, causing scraping of the wafer.